Cat delete,whos is better?

Been doing some research since i have the motor out and torn down,figurd do some little things now.I have seen the standard D plate mods out there from several companies and today I found one through jet works that has no D shape, but more of a choked down restictor type plate.Anyone got input on good or bad between them?
Also whats the free flow mod involve.Yes i do use search but rarely get back what i need in info.Could we maybe have a sticky or just a setion for mods, just one mod per post, even the diy ones?Just a thought,or am i just being lazy....